#region License

// The MIT License
//
// Copyright (c) 2006-2008 DevDefined Limited.
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#endregion

using System;
using DevDefined.OAuth.Framework;

namespace DevDefined.OAuth.Provider.Inspectors
{
  public class TimestampRangeInspector : IContextInspector
  {
    readonly Func<DateTime> _nowFunc;
    TimeSpan _maxAfterNow;
    TimeSpan _maxBeforeNow;

    public TimestampRangeInspector(TimeSpan window)
      : this(new TimeSpan(window.Ticks/2), new TimeSpan(window.Ticks/2))
    {
    }

    public TimestampRangeInspector(TimeSpan maxBeforeNow, TimeSpan maxAfterNow)
      : this(maxBeforeNow, maxAfterNow, () => DateTime.Now)
    {
    }

    public TimestampRangeInspector(TimeSpan maxBeforeNow, TimeSpan maxAfterNow, Func<DateTime> nowFunc)
    {
      _maxBeforeNow = maxBeforeNow;
      _maxAfterNow = maxAfterNow;
      _nowFunc = nowFunc;
    }

    public void InspectContext(ProviderPhase phase, IOAuthContext context)
    {
      DateTime timestamp = DateTimeUtility.FromEpoch(Convert.ToInt32(context.Timestamp));
      DateTime now = _nowFunc();

      if (now.Subtract(_maxBeforeNow) > timestamp)
      {
        throw new OAuthException(context, OAuthProblems.TimestampRefused,
                                 string.Format(
                                   "The timestamp is to old, it must be at most {0} seconds before the servers current date and time",
                                   _maxBeforeNow.TotalSeconds));
      }
      if (now.Add(_maxAfterNow) < timestamp)
      {
        throw new OAuthException(context, OAuthProblems.TimestampRefused,
                                 string.Format(
                                   "The timestamp is to far in the future, if must be at most {0} seconds after the server current date and time",
                                   _maxAfterNow.TotalSeconds));
      }
    }
  }
}